What Is Severe Autism? [Guide To Identifying Severe Autism]

Autism is a spectrum that includes mild, moderate, and severe symptoms.

In general, a person’s level of autism is determined by his or her level of functioning and the level of support required for the individual to remain safe.

What Is Severe Autism?

Severe autism, also known as low-functioning autism or profound autism, is the most challenging type of autism.

A person with severe autism exhibits common signs of autism but to a greater degree than a person with mild or moderate autism. Someone with severe autism may also have symptoms that are distinctive to this level of autism.

If you suspect that your child may be affected by this condition, consider the signs, symptoms, and other tools you can use to identify severe autism.

Signs And Symptoms Of Severe Autism

Children with severe autism require extensive help to function safely in daily life.

While every child with autism is unique, the general signs of severe autism include extensive impairment in multiple areas of development.

Language And Communication

Every child, regardless of ability, can communicate.

However, a child with severe autism may be mute and unable to speak verbally. Or perhaps he or she can talk but repeats a few favorite words and phrases and uses a flat or high-pitched voice.

Despite language and communication deficits, a person with severe autism can communicate. He or she may use gestures, sounds, and behavior to show his or her thoughts, feelings, and needs.

Physical Symptoms

A person with severe autism may experience a variety of physical symptoms that are common to people with autism, such as sleeplessness and gastrointestinal issues.

Unfortunately, language and communication limitations may affect his or her ability to express physical pain. In fact, behavioral issues may stem from physical pain that’s undiagnosed and untreated.

Social Limitations

You may notice that your child with severe autism shows little interest in other people. He or she may prefer to be alone and avoid making eye contact with anyone, including parents or siblings.

Also, he or she may be unable to imitate the movements, sounds, and motor movements of others.


Many children with autism exhibit obsessive preoccupations with a subject or object, but a child with severe autism may have an abnormally intense focus or perseveration on something that interests him or her.

Common preoccupations include trains, computers, and television shows. These preoccupations can occur because of a sensory need or anxiety.

Repetitive Non-Verbal Gestures

Repetitive or self-stimulatory non-verbal gestures help a person with autism express himself or herself and cope with anxiety or sensory challenges.

Also known as stimming, these repetitive behaviors can include:

  • Pacing
  • Spinning
  • Twirling
  • Jumping
  • Toe walking
  • Rocking
  • Hand-wringing
  • Arm flapping
  • Moaning
  • Door slamming

A person with severe autism may repeat these or other behaviors in a manner that ranges from occasional or moderate to extreme, violent, or uncontrolled.

Sensory Processing Disorder

The senses include sight, sound, smell, taste, and touch.

With severe autism, a person may experience sensory processing disorder, which includes severe sensitivities to anything related to the five senses.

He or she may be intolerant of bright lights, including sunshine, startle easily at loud noises, detest unpleasant or strong odors, and avoid crowded environments.

Any environment that includes these factors will be over-stimulating, overwhelming, and intolerable.

Behavior Challenges

Because a person with severe autism cannot communicate clearly with words, he or she may communicate via behaviors. These behaviors may range from impulsivity to aggression.

Typically, they allow a person with severe autism to express excitement, a sensory overload, physical pain, or another emotion or frustration.

Uncontrolled Emotions

You may watch your child with severe autism display a wide variety of emotions. He or she may giggle, cry, or shout randomly.

In most cases, your child will express emotions without cause or reason and have trouble controlling those emotions or knowing when it’s okay to display feelings, which can lead to emotional outbursts at inappropriate times.

Self-Injurious Behavior

Impulsivity, the need for stimulation, an effort to relieve pain, or the inability to communicate may cause a person with severe autism to injure himself or herself.

Self-injurious behavior can include the following:

  • Head-banging
  • Pinching
  • Scratching
  • Pica, or eating non-food items like paper, clothing, or feces


To relieve anxiety or communicate feelings, a person with severe autism may act in an aggressive manner. He or she may kick, hit, or bite.

Other aggressive behaviors include door banging, object throwing, or fecal smearing.

Wandering And Eloping

Eloping occurs when a person with severe autism wanders or runs away with no particular destination or obvious cause.

It can happen impulsively or in response to a frustration or other stimuli, and it can occur at home or in any public location.

Cognitive Impairment

A low IQ can be a sign of severe autism.

Even with a low IQ or mental retardation, though, a person with severe autism can learn to use spelling boards, signs, and other tools.

Understanding Symptoms Of Severe Autism

While there is no test for autism, these signs and symptoms could indicate the presence of severe autism in your child.

Also, realize that sometimes a child may develop normally and meet all developmental milestones until they reach 18 or 24 months of age. At that time, they may lose their ability to speak, stop making eye contact, and show other signs of severe autism.

It’s important as parents to track your child’s milestones and talk with your pediatrician if you suspect any developmental changes. Early diagnosis and intervention can help both you and your child overcome common challenges and improve your quality of life.

You may also be interested in these other autism resources:

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